diff options
Diffstat (limited to 'gcc/sched.c')
| -rw-r--r-- | gcc/sched.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/gcc/sched.c b/gcc/sched.c index 81d77bfd1bd..2be6f9d83fa 100644 --- a/gcc/sched.c +++ b/gcc/sched.c @@ -371,9 +371,11 @@ static rtx canon_rtx (x) rtx x; { + /* Recursively look for equivalences. */ if (GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER && REGNO (x) <= reg_known_value_size) - return reg_known_value[REGNO (x)]; + return reg_known_value[REGNO (x)] == x + ? x : canon_rtx (reg_known_value[REGNO (x)]); else if (GET_CODE (x) == PLUS) { rtx x0 = canon_rtx (XEXP (x, 0)); @@ -390,6 +392,16 @@ canon_rtx (x) return gen_rtx (PLUS, GET_MODE (x), x0, x1); } } + /* This gives us much better alias analysis when called from + the loop optimizer. Note we want to leave the original + MEM alone, but need to return the canonicalized MEM with + all the flags with their original values. */ + else if (GET_CODE (x) == MEM) + { + rtx copy = copy_rtx (x); + XEXP (copy, 0) = canon_rtx (XEXP (copy, 0)); + x = copy; + } return x; } @@ -825,6 +837,8 @@ true_dependence (mem, x) both an unchanging read and an unchanging write. This won't handle all cases optimally, but the possible performance loss should be negligible. */ + x = canon_rtx (x); + mem = canon_rtx (mem); if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) return 0; @@ -849,6 +863,8 @@ anti_dependence (mem, x) /* If MEM is an unchanging read, then it can't possibly conflict with the store to X, because there is at most one store to MEM, and it must have occurred somewhere before MEM. */ + x = canon_rtx (x); + mem = canon_rtx (mem); if (RTX_UNCHANGING_P (mem)) return 0; @@ -870,6 +886,8 @@ output_dependence (mem, x) rtx mem; rtx x; { + x = canon_rtx (x); + mem = canon_rtx (mem); return ((MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) || (memrefs_conflict_p (SIZE_FOR_MODE (mem), XEXP (mem, 0), SIZE_FOR_MODE (x), XEXP (x, 0), 0) |